Standardizing only makes sense for types of projects that are repeated often and would be more valuable if they were done the same way each time.
Doing something the same way each time has two advantages — the first is efficiency, since the problem doesn’t have to be re-solved each time, and the second is consistency.
If something doesn’t come up often, efficiency isn’t an issue, since any attempt at standardization is going to be based on too few data points (as they don’t occur often) and probably take longer than addressing the projects one at a time. And if it’s not going to be seen in the context of other examples of the same kind of project, consistency isn’t an issue either.
That means these projects are excellent opportunities for designers to do what they do best — interpret the brand. If given the right resources, they can be opportunities to stretch the boundaries of the brand, to help it grow and evolve. Embrace them.